Since the inception of electromagnetic theory and the discovery of radio frequency transmission, antenna design has been an integral part of virtually every telemetry application. Countless books have been written exploring various antenna design factors such as geometry of the active or conductive element, physical dimensions, material selection, electrical coupling configurations, multi-array design, and electromagnetic waveform characteristics such as transmission wavelength, transmission efficiency, transmission waveform reflection, etc. Technology has advanced to provide unique antenna designs for applications ranging from general broadcast of RF signals for public use to weapon systems of highly complex nature.
Prior to the issuance of U.S. Pat. Nos. 5,594,456 and 5,990,837 of the present inventor, there were two particular areas of prior art related to the present invention. First, U.S. Pat. Nos. 4,028,707 and 4,062,010 illustrate various antenna structures consisting of wire and metal conductors that are appropriately sized for antenna operation with ground penetrating radar. Second, U.S. Pat. Nos. 3,404,403 and 3,719,829 describe the use of a plasma column formed in air by laser radiation as the antenna transmission element.
In its most common form, the antenna represents a conducting wire that is sized to radiate or receive signals at one or more selected frequencies. To maximize effective radiation of such energy, the antenna is adjusted in length to correspond to a resonating multiplier of the wavelength or frequency to be transmitted. Accordingly, typical antenna configurations will be represented by quarter, half, and full wavelengths of the desired frequency. Effective radiation means that the signal is transmitted efficiently. Efficient transfer of RF energy is achieved when the maximum amount of signal strength sent to the antenna is expended into the propagated wave, and not wasted in antenna reflection. This efficient transfer occurs when the antenna is an appreciable fraction of transmitted frequency wavelength. The antenna will then resonate with RF radiation at some multiple of the length of the antenna.
Reflector antennas have been in use since about the time of discovery of electromagnetic wave propagation by Hertz. However, many years later when radar applications began evolving rapidly, the demand for reflectors caused many different designs to be fabricated. Additionally, reflectors for use in radio astronomy, microwave communication, and satellite tracking has resulted in great progress in the development of sophisticated analytical and experimental techniques in shaping the reflector surfaces and optimizing illumination over their apertures so as to maximize gain. Though reflectors take on many different shapes and sizes, popular shapes are plane, corner, and curved reflectors (especially the paraboloid). Additionally, similar structures have been used to provide electromagnetic shielding. For example, a reflector can be placed in front of an object to shield it from electromagnetic radiation.